To realize process intensification, active species like radicals and their mass transfer need to be considered. A two-layered catalyst bed reactor was used to investigate the participation of radicals in two different reaction processes. Two-layered catalyst bed (2LCB), mixed catalyst beds (MCB) and separated catalyst beds (SCB) were compared in oxidative coupling of propane. The dependency on the contact time for the concentration of propylene in the effluent was almost constant at experimental conditions. However, that of benzene with 2LCB and MCB was higher than SCB, especially at a lower flow rate. The quartz sand layer for SCB between the catalyst beds prevented the highly active intermediate generated in the first layer from being transferred in the gas phase to the second layer. This result supports the idea of the participation of the active intermediate in the direct coupling to benzene.